Valve for controlling fluid pressure



Nov. 8, 1932. L fLTfNETTLETN A 1,887,322

VALVE FOR CONTROLLING FLUID PRESSURE Filed Sept. 29, 1928 MI// %ENTOR Patented Nov. 8, 1932 UNITED STATES LEV/IS L. NETTLE'EDN, OF EDGEVJOOD, 4IYENN'SYLVANLA.

'p YVALVE ,ron eonraornrne FLUID PRESSURE y i Application filedl September 29, w28. Serial No. 309,217. v

My invention relates to valves for control ling Huid pressure. l

I willdescribe several forms of valves embodying my invention, and will then point 8 out the novel features thereof in claims.

The present case is in part a continuation of my (io-pending application, Serial No. 273,883, led April 30', 1928, for signaling apparatus. l d l Y v In the accompanying drawing, Fig. 1 is a diagrammatic view illustrating one formof valve embodying myinvention applied to a receiver fortrain-brake pipe signals. Fig. 2 isa View showing one form of valve emlbodying my invention applied to a pneumatic amplifier. `Fig. 3 is a view showing a fee'd valve embodying my invention. Similar reference characters refer to similarparts in each of the three views. p

Referring first to Fig. 1, the reference character A designates a train brake pipe which isnormally supplied with -fluid pressure, usually air under pressure, and which controls the brake applying apparatus in the usual and well known manner.V A reservoir'R is connected with the brake pipe YA through a restricted orifice 01. The-brake pipe is provided with signal transmitting means which form no part of my present invention, but

which are adapted to impress pressure pulsations on the-air in the brake pipe. These impulses may be either increases of brake pipe pressure or decreases of brakel pipe pressure, and they may for example,'be caused by apparatus similar tothe transmittingapparat-us disclosed in my co-pending application for Letters `Patent of the UnitedStates, Serial No. 238,567, filed December 8, 1927, for

signaling apparatus and methods. The Ie- 40 ceiving apparatus includes a pneumatic am# pliier comprisingV a body member 2 and a cover 3 which are clampedtogether by bolts il, with a diaphragmV D1 interposed between the bodyrmember and the cover. Mounted vwithin the body member 2 is a member 5 having a passage 12 between vtwo opposing valve seats 13 and 13a. Valve stem 6 extends throught-he passage 12 and is provided-with two valve elements 14 and-14;a (1o-operating with the valve seats 13and13a to form valves length of time such that the pressures in all parts ofthe apparatus havereachedan equi- -`the opening of valve V.

light lamp S. Y

V and Va', respectively. l Valve'stem 6v is operatively connected with the .diaphragm D1 and is urged upwardly by 'a spring 10- which may beadjusted yby a. screw 11. The upper side of diaphragm D1 is'subj-ected to the pres- ,'55 sure in reservoir R and the lower side of this dia} hragmis subjected tothe pressure in the brake pipe A. Y Y Y vA pneumatic relay F is connected, through an auxiliary pipe P with the passage 12 ina-,.60 member V5. Y The relay F vcomprisesa diaphragm D2, the lower side of whichV issubjected to the press-ure existing in pipe P. The diaphragm D2 operates a contact K which controls the supply of current to a signal S ,6,5

from a battery B.

In explaining the operation of the apparatus, I will first assume, that thepressure in the brake pipe A has beenconstant for a libriuni. ,'rlhepressures on the two sides Y. of diaphragm`D1 yare therefore equal, and the pressure vof springklO is adjustedbyvscrew 11.so that under theseyconditionsvalvesV and V arefboth open. VA small stream of air therefore flowsfronfi` the brake pipe A, throughvalve V, passage 12, and valve VSL to atmosphere through the ports 15.l 1 The total drop in yfluid pressure from the-brackets() pipethroughvalves, V and Vato atmosphere ydivides betweenthese' two valves'so Ithat Vthe pressure in pipe Pis intermediate between the brake pipe pressure and atmosphere. The parts' of relayF are sov adjusted that .the pres- '35 surethus supplied to diaphragm D2 is l not suiiicient to close contact K, and y lamp Sis therefore extinguished.

I will next assume thatthere is aV small ini crease in the pressure in brake pipeAQ.,l This pressure change lcauses a higher pressure on the lower side of diaphragm D1 than: onthe upper: side of the diaphragm so that dia* Yphragm D1 bulges upwardly, thereby decreasing the` opening of valveV@ and vincreasing Both Vof .these changesfincrease the pressure in pipe P so that thepressure onth'e, underside of diaphragm D2 increases and contact K closesto y port of this valve stem.

In order to operate the relay F in i'espense to very small changes in the pressure in the brake pipe, it is obvious that the valve stein 6 must be operated by extremely small amounts of energy. It is therefore desirable to eliminate the eii'ects of friction in the sup- I prefer to accomplish this result by supporting the valve stem 6 by a plurality of elastic metallic strips 7.

@ne end ot each strip 7 is attached to thek valve stein 6 by clamp 9 and the other end of the strip 7 is attached to the member 5 by a clamp 8. Preferably, one set of strips 7 is located on the upper side 4o1c member 5` and another set ot strips 7 is located on the lower side of member 5, the 'upper and lower'taces of tl'iisinember being'recess'ed to accommodate the, strips 7 and the clamps 9. The strips 7 extend radially from the valve stem 6 and are drawn to the desired tension with the valve stem 7 centered with respect to t Le valve seats, and the strips are hen attached Y to the member 5 by the clampst. Ii/Vith this construction, the valve stem 6 is reeto move vertically without friction, and it encounters no frictional oppositionuntil eiti er valveV V orV' is completely closed. I have found that the ampliiier E shown in Fig. 1 may be constructed to operate ya standard pneumatic relayF for the control of signal S in response to changes in the position of the valve stem 6 of the order of .O01 oi an inch.

Referring now to Fig. 2, the valve stem 6 contained in the body member 2 is similar to the corresponding part previously described in connection with Fig. 1 with the exception sure not shown in the drawing, and the pneuthat the valve stemis operated byan electromagnet M instead of by the diaphragm D1.

The chamber above valve V is connected, by means of pipe 26, with a sourceof fluid presmatic relay F is responsive to the pressure in passage 12 as in Fig.,1. The apparatus here shown may be actuated by Vsmall amounts of electrical current. In the form here shown electromagnet M is assumedto be apartof a l train control system in 4which the train carried apparatus is responsive to currents flowing in the track rails. The reference charlacters 16 and 16a designate the track rails of a stretch of railway track which are at times supplied with Vcurrent which is periodically varied in accordance with traine conditions. In one form of train control system of the type described, the track rails are supplied with alternating current which is periodicallyinterrupted at different frequencies depending upon traiiic conditions. The ref- 'erence character R designates a receiver provided with two windings 18 and 18'L in inductive relation with the track rails 16 and which in the form here shown comprises a magnetizable core 17 located in inductive i'elation with the track rails. The core 17 is 16a, respectively, and connected in series in infr/'32e such manner that electiomotive forces iiiduced in these windings by train controlling currents in the track rails 16 and 16 are additive'. The receiver windings 18 and 18a may be tuned to resonance at the frequency ot the train controlling current by means of a coiidenser 19, andare connected through a filter 20 and a rectifier 21 with windings 23 and 23L Vof the electromagnet M. The electromagnet M comprises a` magnetizable core 22 which carries the windings 23 and 23a, and an armature 2twliich is connected, by means of a rod 25, with the valve stem 6. The parts vare so adjusted and proportioned that under normal conditions, for example, when uninterrupted alternating current is being supplied to rails 16 and 16a, the valve stemV 6 under the ini'iuence of spring 10 occupies a. position in which valves V and V2L are opened by such amount that the pressure then existing iii pipe P moves diaphragm D2 to a position in which contact "Kl-K1 is open.y If the current in the track railsv is interrupted, thecurrent supplied to the windings of the electromagnet M is interrupted, and spring 10 then moves valve stein 6upwardly to vopen valve V and close valveV. Both of these effects increase the pressure in pipe P,whereupon the pneumaticrelay F is operatedto close contact IIC-K1. i TVVhen the current in the track rails" is reestablished, the electromagnet M is again energized to' close valve V and open valve Va. As a result, therpressure in pipe l? is reduced and contact K-Kl of pneumatic vrelay F is opened. The contact K-K1 may'Hiv be used to control otherv apparatus, notillustinted, in any suitable manner. Under some conditions 1t may be desired to add a second .Xedcont-act K2 and adjust the apparatus` in such mannervthat the-contact swings alterf" nately intoengagement with contacts K1 and K2 when the current in the track rails is periodically interrupted.

It should Vbe observed that although in the discussion just preceding, I have spoken of' opening and closing of valves V and V, it should be distinctively understood that any Y movement of the valve stein 6, no matter how slight, will result in some change in the rela-l standard pneumatic relay F.

Electropneumatic ampliiers of the type shown in Fig."2 are rugged in construction, simple in operation, and may be constructed to have avery large amplification constant.

IIC

ti l) In the form of apparatus shown in Fig. 3, I have illustrated a feed valve of the type customarily employed inV railway air brake suitable source of fluid pressure not shown in the drawing. An outletv port 36 is c'onnected with the apparatus which it is desired to supply with fluid pressure. The outlet port 36 will usually be connected through the enffinemans brake valve with the train brake pipe. A slide valve 3l controlled by a piston 29 and provided with a port 3 2 regulates the opening between the inlet port 28 and the outlet port 3G, the piston 29 being biased by spring 30 into a position in which port 28 is closed. The underside of piston 29 is connected with the inlet port 28 through port 33, and the upper side of piston 29 is connected through pipe P with a passage 12 in a mem-` ber 5 similar to the corresponding part in Figs. l and 2. Passage l2 contains a lvalve stem 6 supported by radially extending elastic strips 7 in the same manner as was described in connection with Figs. l and 2. The valve stem 6 is urged downwardly by a spring 26 operating on a diaphragm D3, the lower surface of which is subjected to the pressure in the outlet port 36, with which it is connected by means of port 35. The valve stem 6 is urged upwardly by the spring i0, the chamber beneath valve Va being connected, through ports 3ft and 33, with the inlet port 28.

In operation air flows from the inlet port 28, through port 32, to the outlet port 36. A stream of air also flows from port 28, through ports 33 and 34, valve V, passage l2, valve V,

and port 35 to port 36. If the pressure in Y the outlet port 36 decreases, the pressure on the underside of diaphragm D3 decreases, and spring 2G moves valve stem 6 downward-- ly to close valve Va and open valve V. The pressure in pipe P, and hence the pressure above piston 29, is therefore decreased and the pressure on the underside of this piston nieves the piston upwardly to increase the opening of p-ort 32 between the inlet and outlet ports. The pressure in the outlet port is. thereby increased. If, on the other hand,I the pressure on the outlet port increases: above the value determined bythe force exerted by spring 26, the diaphragm D3 is. moved upwardly, thus allowing spring 10' to move valve stem 6 upwardly. As a result of this movement of the valve stem, valve V' is closed and valve Va is opened. Both of these changes increase the pressure in pipe P, and hence' above the piston 29. The piston is therefore moved downwardly to decrease the opening between the inlet port 28 and the outlet port 36. It will be seen from the foregoing explanation that for any given value of the pressure caused by spring 26, an infto vary the relative crease in the pressure. in the outlet port 36 above this pressure, will cause almovement of the slide valve 3l in one direction and a decrease in the pressure in the outlet port 36 below this value will cause a movement of the slide valve in the opposite direction. One advantage of the apparatus embodying my invention over feed valves hereto known 1s that a very small change in the outlet port pressure will causea change in the position of the valve stem .6. Since the movement of this valve stem is not opposed by friction, it

follows that extremely close regulation of the outlet port pressure may be accomplished, because the valves V and Va change their rel ative openings in response to small changes in the pressure on the underside ofthe diaphragm D3..

. Although I have herein shown and de-` scribed only a few forms of valves embodying` changes and modifications may be made therein within the scope of the appended l. In combination, a fixed member,`a valvev stem, a plurality of stretched elastic strips each having one end attached to said stem and 5 the other end fixed withrespect to said 4member, a pipe, a source of liuid pressure, two

valves controlled by said stem one of which connects said source with said pipe and the other of which connects said pipe with atmosphere, and means for operating said stem openings of vsaid twoy valves.

2. VIn combination, a valve stem, a plurality of radially extending elastic strips each :attached to said stem at the inner end of the strip and fixed at the outer end, a valve controlled by said stem, a winding suppliedwith varying current, and means for moving said :stem in accordance with variations in said current. l

3. In combination, a valvestem, a plural- :ity of radially extending elastic strips each attached to said stem at the inner end of the :strip and fixed at the outer end, a source of ifluid pressure, a pipe, two valves controlled by said stem one of which connects said pipe with said source and the other of which coninects said pipe with atmosphere, and an electromagnetfor operating said stem. l In testimony whereof I aiiix my signature.

LEVIS L. NETTLETON.

-my invention, it is understood thatvarious Y 

